Fault & Cause Flashcards

1
Q

List 4 commonly found faults in the wheels and tyres

A

Tread wear/pattern unsuitable for road surface
Wheels/tyres of different sizes
Insufficient/excessive tyre pressure
Incorrect wheel bearing adjustment

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2
Q

List 4 commonly found faults in the steering and suspension

A

Worn ball joints and suspension bushes - cause unpredictable wheel movements that reduce grip
Worn springs and dampers - cause wheels to lose grip from leaving road surface
Worn steering gear and track rod ends - too much play will cause unpredictable wheel movements that reduce grip
Incorrect wheel alignment and steering geometry will cause one or more tyres to scrub across the road surface

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3
Q

List 4 commonly found faults in the brakes

A

Incorrect free play, pedal height or operation of brake lights
Hydraulic leaks or low brake fluid - cause ineffective and spongy brakes, lacking pressure
Vapour lock, caused by water in the hydraulic fluid
Worn friction material in the brake assembly - causes overheating and brake fade

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4
Q

List 4 possible faults that could cause inefficient brakes

A

Worn friction material, overheating and causing brake fade
Incorrect servo operation - possible vacuum leak
Hydraulic fluid leak - tandem master cylinder only operating on one part of the system
Air in the hydraulic system - causes spongy brakes and loss of leverage in the pedal

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5
Q

List 3 possible faults that could cause pulsation at the brake pedal

A

Anti-lock braking system cutting in too early - possibly caused by worn tyres
Excessive wheel bearing play - causes brake discs to move the brake pads back in the caliper
Excessive run-out - caused by warp brake disc or brake disc thickness variation, known as ‘martensite deposits’

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6
Q

List 2 possible faults that could cause tyre skid/an illuminated ABS warning light

A

Worn tyres, causing them to slide on the road surface
Fault with the ABS

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7
Q

List 9 faults that can cause light steering

A

Excessive tyre pressure
Tyre wear, causing loss of grip
Incorrect wheel alignment and steering geometry
Excessive play in steering and suspension linkages
Flow control valve stuck or closed
Broken rotary control valve torsion bar spring
Speed sensitive solenoid valve stuck open
Vehicle speed sensor (VSS) signal too low
Speed sensor ECU fault

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8
Q

List 9 faults that can cause heavy steering

A

Insufficient tyre pressure
Incorrect wheel alignment and steering geometry
Partial seizure in steering and suspension linkages
Low power steering fluid
Broken or slack drive belt
Worn hydraulic pump
Flow control valve stuck open or faulty
Hydraulic piston leak
Speed sensor control system failed

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9
Q

What fault can cause hard suspension? How can this be diagnosed?

A

Worn springs allowing suspension to contact the bump stops
Measure the suspension ride height and visually inspect the condition of the road springs

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10
Q

What fault can cause excessive spring oscillation? How can this be diagnosed?

A

Leaking dampers
Conduct a bounce test by pushing down and releasing the suspension and assessing the damping action. Visually inspect the dampers for leaks

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11
Q

What fault can cause noise in the suspension? How can this be diagnosed?

A

Worn suspension bushes
Raise the vehicle and check the suspension bushes for excessive play, using a pry bar

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12
Q

What fault can cause the car’s ride height to be too low? How can this be diagnosed?

A

Broken road spring
Measure the ride height and visually inspect the springs for damage

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13
Q

What fault in the supercharger or turbocharger could cause noise?

A

Bearing wear. Because of high rotational speeds, lubrication is essential. Dirty, unattended-to oil can cause insufficient lubrication. Evidence that the turbine bearings are worn is if you move the turbine spindles with your fingers and find that there is excessive free play.

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14
Q

What fault in the supercharger or turbocharger could cause high volumes of oil/blue smoke coming from the exhaust?

A

Leaking lubrication oil out of the seals around the drive spindle, caused by excessive free play and wear in the bearings.

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15
Q

If there is oil smoke coming from the exhaust, what’s a way to find out if the oil leak occurs before or after the engine?

A

Remove the spark plugs and check them for fouling. If they do not show signs of oil contamination, oil has likely entered the exhaust system after the engine.

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16
Q

What can be looked for to check if the spindle seals in the turbo is leaking oil?

A

Contamination or carbon build up on the turbines

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17
Q

List 3 faults that could cause a loss of boost in the turbocharger or supercharger? When should you check for these 3 faults?

A

Restriction in the air intake system
Leakage on the pressure side of he engine intake system
Wastegate seized in the open position
Check these before you assume there is a fault with the turbine or supercharger itself

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18
Q

What fault could cause overboost in the turbo? How can this be checked?

A

A wastegate seized in the closed position
Examine it using a pressure pump or vacuum pump

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19
Q

What fault could cause loss of cylinder compression in the variable valve control? What can this lead to? How can this be diagnosed?

A

Leaking/insufficiently sealed inlet or exhaust valve
Valves overheating and burning out
Use a compression test or cylinder leakdown test

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20
Q

What fault could cause the performance not to change during operation in the variable valve control? How can this be diagnosed?

A

Oil pressure lost to valve control mechanisms, meaning variable valve timing won’t be available
Check the oil level, pressure and condition

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21
Q

What fault could cause noise in the variable valve control? How could this be diagnosed?

A

If the oil quantity, pressure or condition is poor, there will be excessive noise in the hydraulic tappets (although not all cars have hydraulic tappets)
Isolate the location of the noise using a technician’s stethoscope, then remove the engine covers and check for excessive play or wear in the tappets

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22
Q

What fault could cause oil smoke in the variable valve control?

A

Oil leaking pat the valve stem oil seals and getting burned within the combustion chamber

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23
Q

List 2 faults that can cause piston damage in the engine

A

Physical impact
Overheating

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24
Q

List 3 faults that can cause hydro-locking in the engine, which could result in bent connecting rods

A

Severely leaking head gaskets
Excessive over-fuelling
Water entering through the air intake

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25
Q

List 2 faults that can cause structural failure in the engine block. How can this be rectified?

A

Mechanical component failure
Frozen coolant
Completely replacing short engine components

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26
Q

What fault can cause broken or seized piston rings in the engine? Give a tip that can help when replacing piston rings

A

Overheating due to friction
Use part of an old broken piston ring as a scraper to clean out the grooves

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27
Q

List 3 faults that can cause crankshaft damage in the engine

A

Wear and tear caused by operation of a cylinder power stroke
Vibrations created by an imbalance of piston operation
Insufficient lubrication

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28
Q

What could woodruff key failure in the engine result in?

A

The pulleys spinning on the shaft and the valves, which cause excessive wear and/or valve timing issues

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29
Q

Name a fault that can cause tapping in the engine

A

Cam lobe/follower wear

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30
Q

List 7 faults that can cause cam belt failure in the engine

A

Incorrect tension (too loose or tight)
Poor maintenance (too long between being replaced)
Not fitted correctly
Contamination by oil, coolant or dirt
Pulley bearing failure, creating friction and heat
Fouling of engine components (stuff rubbing on it)
Worn sprockets

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31
Q

What fault can cause bent valves in the engine?

A

Sudden failure of the valve drive mechanism, resulting in collision of the pistons and valves

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32
Q

Name a fault that can cause sudden loss of pressure in the engine

A

Rapid seizure of the engine, caused by friction between the engine and mechanical components, sometimes caused by loss of oil pressure, because of a failed oil pump

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33
Q

What fault could cause the ignition not to produce a spark?

A

Open circuit in the crankshaft position sensor, so there is no engine speed signal being produced

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34
Q

What fault could cause the ignition to misfire?

A

Ignition coil windings with high resistance, causing it to break down under load

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35
Q

What fault could cause the ignition to backfire?

A

Incorrect ignition timing, causing fuel to ignite in the inlet manifold

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36
Q

What fault could cause cold/hot starting problems in the ignition?

A

Fouled spark plugs, caused by incorrect operating heat range

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37
Q

What fault could cause poor performance in the ignition?

A

High resistance plug leads, giving a weak spark under acceleration

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38
Q

What fault could cause pre-ignition?

A

Spark plug earth electrode overheating, igniting the fuel before the spark, cause by the incorrect spark plug being used

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39
Q

What fault could cause detonation in the ignition?

A

Petrol spontaneously igniting cause by fuel with too-low octane rating

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40
Q

What fault in the ignition could cause excessive exhaust emissions?

A

Retarded (late) ignition timing, causing combustion temperatures to rise, creating excessive nitrogen oxides

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41
Q

What fault in the ignition could cause high fuel consumption?

A

Incorrect spark plug gaps, causing uneven running and leading to excessive fuel consumption

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42
Q

What fault could cause lack of power in the ignition?

A

Advanced (early) ignition timing, causing pressure build-up when the connecting rod is vertical

43
Q

What fault in the ignition could cause unstable idle speed?

A

Loose reluctor ring, causing variable engine speed signals

44
Q

What fault could cause excessive hydrocarbon production in the exhaust?

A

Engine misfire, allowing unburnt fuel into the exhaust system

45
Q

List 2 faults that could cause excessive carbon monoxide production in the exhaust

A

Insufficient oxygen in the combustion process (rich mixture)
Possible leaking injector

46
Q

List 2 faults that could cause insufficient carbon monoxide production in the exhaust?

A

Excessive oxygen in the combustion process (weak mixture)
Possible induction air leak

47
Q

List 2 faults could cause insufficient carbon dioxide production in the exhaust?

A

Engine mechanical condition/efficiency fault
Possible low compressions

48
Q

What fault could cause excessive oxygen production in the exhaust?

A

Too much oxygen entering intake or exhaust

49
Q

List 2 faults could cause insufficient oxygen production in the exhaust?

A

Engine running rich
Possible blockage in the air intake

50
Q

List 2 faults in the fuel injection system could cause cold or hot starting problems

A

Incorrect coolant temperature sensor signal, affecting fuel injection quantity
Faulty glow plugs on a diesel engine

51
Q

What fault in the fuel injection system could cause poor performance?

A

EGR valve stuck open, reducing volumetric efficiency and performance

52
Q

What fault in the fuel injection system could cause excessive exhaust emissions?

A

Fuel pressure regulator stuck closed, raising injection pressure and making the engine run rich (low oxygen)

53
Q

What fault in the fuel injection system could cause high fuel consumption?

A

Incorrectly adjusted throttle position sensor, meaning the engine load is miscalculated and the engine is over-fuelled

54
Q

What fault in the fuel injection system could cause erratic running?

A

Open circuit mass airflow sensor, leading to incorrect air quantity measurement

55
Q

What fault in the fuel injection system could cause low power?

A

Blocked fuel filter, reducing the amount of fuel available for injection an reducing power because of starvation

56
Q

What fault in the fuel injection system could cause unstable idle speed?

A

Induction air leak, allowing unmetered air to enter the engine, which causes surging

57
Q

What fault could cause leaks in the air conditioning system?

A

Damage to condenser radiator caused by front end collision

58
Q

What fault could cause an abnormal noise in the air conditioning system

A

Worn and slipping compressor drive belt

59
Q

What fault could cause ineffective operation in the air conditioning system

A

Failed climate control servo motors resulting in ventilation flaps not moving

60
Q

What fault could cause failure to operate in the air conditioning system

A

Low pressure/quantity of system refrigerant gas resulting in the compressor clutch not engaging

61
Q

What fault could cause control faults in the air conditioning system

A

Unadjustable fan speed due to burnt-out rheostat controller

62
Q

What fault could cause inadequate operation in the air conditioning system

A

Frozen evaporator core due to faulty temperature thermistor measurement

63
Q

(By the way, there was a section I skipped in the electrical section, because it was too long and I didn’t understand it. The symptom and use/test section on pg. 191 will be in the electrics section)

A
64
Q

Give a symptom for and open circuit in the lighting systems
Give one for high resistance in the lighting systems

A

Sidelight not working
Nearside dip beam headlamp in dim

65
Q

Give a symptom for and short circuit in the lighting systems
Give one for a parasitic drain in the lighting systems

A

Brake light circuit fuse blows when brakes are pressed
Car battery goes flat overnight

66
Q

What fault can cause an open circuit in the lighting systems?

A

Filament burnt out in the bulb, breaking the circuit and interrupting the current flow

67
Q

What fault can cause high resistance in the lighting systems?

A

Corroded earth connection on nearside dip beam circuit that shares the voltage with the bulb and reduces its performance

68
Q

What fault can cause an short circuit in the lighting systems?

A

Braked light wire chafed on bodywork before reaching the bulb, creating a short cut to the earth

69
Q

What fault can cause a parasitic drain in the lighting systems?

A

Incorrectly adjusted boot light switch so that the bulb stays illuminated even when the boot is closed

70
Q

What fault can cause an open circuit in the electric window and mirror systems? Give one symptom

A

Electric feed wire to the drive motor broken at the door hinge because it is flexed backwards and forwards a lot
Electric mirror adjustment not working

71
Q

What fault can cause high resistance in the electric window and mirror systems? Give one symptom

A

Poor connection at the door window motor, creating a resistance which shares the voltage with the window motor and reduce its performance
Electric window slow to operate

72
Q

What fault can cause a short circuit in the electric window and mirror systems? Give one symptom

A

Wire trapped against the metal bodywork where the mirror is bolted to the frame, creating a short-cut to the earth
Damaged wiring to offside electric mirror

73
Q

What fault can cause a parasitic drain in the electric window and mirror systems? Give one symptom

A

Faulty electric window switch, causing power to be transmitted to the motor in the up direction even when it is not pressed
Car battery goes flat overnight

74
Q

What fault can cause an open circuit in the heated windscreen system? Give one symptom

A

Window element broken/damaged at the mid-point of the windscreen, caused by load/luggage rubbing against it
Heated windscreen not working

75
Q

What fault can cause high resistance in the heated windscreen system? Give one symptom

A

Burnt contact in the contact relay, creating a resistance which shares the voltage with the heater element and reduces its performance
Demister slow to operate

76
Q

What fault can cause a short circuit in the heated windscreen system? Give one symptom

A

Wire rubbed against the bodywork before the front screen element, creating a short-cut to earth
Heated rear screen fuse blown/burnt out

77
Q

What fault can cause a parasitic drain in the heated windscreen system? Give one symptom

A

Circuit timer failure,l causing the screen not to switch off after a predetermined timescale
Car battery goes flat overnight

78
Q

In the mechanical clutch cables:
What causes clutch slip?
What causes clutch drag?
What causes clutch judder?
What causes a stiff clutch?

A

Insufficient free play
Excessive free play
Lack of lubrication or wear
Incorrect routing, making the clutch cable all bent

79
Q

In the hydraulic operating system:
What causes clutch slip?
What causes clutch drag?

A

Fluid contamination of the friction plate from a leaking direct acting slave cylinder
Air in the hydraulic system, causing sponginess and not allowing complete disengagement of the clutch mechanism

80
Q

What fault can cause a rattling noise in the clutch and coupling?

A

Worn damping springs in dual mass flywheel

81
Q

What fault can cause vibrations from the crankshaft in the clutch and coupling?

A

Crankshaft pulsations transferred to transmission

82
Q

What fault can cause fluid leaks from the slave cylinder in the clutch and coupling?

A

Seal failure in slave cylinder

83
Q

What fault can cause clutch grab/snatch in the clutch and coupling?

A

Incorrect information from clutch position sensor

84
Q

What fault can cause a rumbling noise in a manual gearbox?

A

Worn main shaft support bearings

85
Q

What fault can cause vibrations while in a particular gear in a manual gearbox?

A

Broken gear teeth on that particular gear

86
Q

What fault can cause the car not to be able to move in a manual gearbox?

A

Interlock failure, allowing two gears to be engaged at the same time

87
Q

What fault can cause difficulty engaging or disengaging gears in a manual gearbox?

A

Hydraulic pressure to one clutch lost due to failed control solenoid valve

88
Q

What fault can cause a rumbling noise in an automatic gearbox?

A

Worn planet gear support bearings

89
Q

What fault can cause vibration created by overrun/deceleration in an automatic gearbox?

A

Damaged sprag in one-way clutch

90
Q

What fault can cause the car not to be able to move in an automatic gearbox?

A

Low automatic transmission fluid level

91
Q

What fault can cause failure to engage gear in an automatic gearbox?

A

Worn brake band

92
Q

What fault can cause failure to disengage gear in an automatic gearbox?

A

Clutch pack 2 hydraulic pressure not releasing

93
Q

What fault can cause ATF (automatic transmission fluid) to leak in an automatic gearbox?

A

Gearbox sump pan gasket failure

94
Q

What fault can cause failure to operate in an automatic gearbox?

A

Shift position sensor failure

95
Q

What fault can cause the gear change to happen too late in an automatic gearbox?

A

Incorrect signal from vehicle speed sensor

96
Q

What fault can cause incorrect electric component operation in an automatic gearbox?

A

CAN bus network failure

97
Q

What fault can cause whine on overrun/deceleration in the final drive?

A

Incorrect tooth contact between crown wheel and pinion

98
Q

What fault can cause vibrations in the final drive?

A

Ineffective differential , causing the road wheels to slip when turning

99
Q

What fault can cause the car to not be able to move in the final drive?

A

Broken planet gear drive pin

100
Q

What fault can cause oil leaks in the final drive?

A

Ineffective pinion gear oil seal

101
Q

What electrical fault can cause a lack of differential control in the final drive?

A

Excessively high resistance electromagnet

102
Q

What fault can cause a clicking noise when turning/cornering in the driveline and coupling?

A

Worn CV joint

103
Q

What fault can cause vibrations when moving faster than 20 mph in the driveline and coupling?

A

Bent drive shaft

104
Q

What fault can cause the car not to be able to move in the driveline and coupling?

A

Broken prop shaft universal joint